Abstract: A monitor on-board an aircraft which uses radio altitude measurements as the basic observable altitude during runway approach. The basic concept utilizes the aircraft's navigation system, which includes means to store and retrieve radio altitude thresholds as a function of the distance along the desired path from the runway thresholds. These threshold functions are determined in advance based on a radio altitude reference which is defined as the expected radio altimeter measurement that would be made if the airplane were exactly on the desired reference path. Vertical containment monitoring is achieved by comparing the radio altitude measurement to computed thresholds for both too high and too low. During the approach, an annunciation message can be generated if the radio altitude measurement is above or below the threshold limits.

Abstract: A monitor on-board an aircraft which uses radio altitude measurements as the basic observable altitude during runway approach. The basic concept utilizes the aircraft's navigation system, which includes means to store and retrieve radio altitude thresholds as a function of the distance along the desired path from the runway thresholds. These threshold functions are determined in advance based on a radio altitude reference which is defined as the expected radio altimeter measurement that would be made if the airplane were exactly on the desired reference path. Vertical containment monitoring is achieved by comparing the radio altitude measurement to computed thresholds for both too high and too low. During the approach, an annunciation message can be generated if the radio altitude measurement is above or below the threshold limits.

Abstract: An onboard monitor that ensures the accuracy of data representing the calculated position of an airplane during final approach to a runway. This airplane position assurance monitor is a software function that uses dissimilar sources of airplane position and runway data to ensure the accuracy of the respective data from those dissimilar sources. ILS data and GPS or GPS/Baro data are the dissimilar sources of airplane position data used by this function. This function will calculate the airplane's angular deviations from the runway centerline and from the glide slope with onboard equipment and then compares those angular deviations to the ILS angular deviation information.

Abstract: A method, apparatus, and computer program product for detecting anomalies in a landing system. In one embodiment, a magnitude difference between a blended inertial deviation magnitude and a raw deviation magnitude is identified to form a magnitude difference. The magnitude difference is compared to a magnitude threshold. If the magnitude difference exceeds the magnitude threshold, an anomaly in the data is detected.

Abstract: A monitor on-board an aircraft which uses radio altitude measurements as the basic observable altitude during runway approach. The basic concept utilizes the aircraft's navigation system, which includes means to store and retrieve radio altitude thresholds as a function of the distance along the desired path from the runway thresholds. These threshold functions are determined in advance based on a radio altitude reference which is defined as the expected radio altimeter measurement that would be made if the airplane were exactly on the desired reference path. Vertical containment monitoring is achieved by comparing the radio altitude measurement to computed thresholds for both too high and too low. During the approach, an annunciation message can be generated if the radio altitude measurement is above or below the threshold limits.

Abstract: A method, apparatus, and computer program product for detecting anomalies in a landing system. In one embodiment, a magnitude difference between a blended inertial deviation magnitude and a raw deviation magnitude is identified to form a magnitude difference. The magnitude difference is compared to a magnitude threshold. If the magnitude difference exceeds the magnitude threshold, an anomaly in the data is detected.

Abstract: An aircraft local area augmented landing assistance system that employs a differential global positioning system (GPS) to assist aircraft (102) landing is disclosed. One or more GPS ground stations (120), each including at least one GPS receiver (122) and a datalink transmitter (126), calculate and transmit GPS correction data to an aircraft (102). An aircraft (102) employs a GPS receiver (106) for receiving ranging signals (112) from GPS satellites (108), and a datalink receiver (116) for receiving GPS correction data from a GPS ground station (120). The ground station datalink transmitter (126) employs code division multiple access spread spectrum techniques to transmit a datalink signal (128) that is QPSK modulated within the VHF navigation band. The datalink signal (128) is additionally used as a ranging signal by the aircraft, to augment the differential GPS.

Abstract: An aircraft local-area augmentation system that employs a differential global positioning system (GPS) to assist aircraft (102) landing is disclosed. One or more GPS ground stations (120), each including at least two GPS receivers (122) and a datalink transmitter (126), calculate and transmit GPS correction data to an aircraft (102). An aircraft (102) employs a GPS receiver (106) for receiving ranging signals (112) from GPS satellites (108), and a datalink receiver (116) for receiving GPS correction data and other information from a GPS ground station (120). The aircraft (102) further includes a data processor (110) for determining a global position of the aircraft (102) as a function of the aircraft GPS pseudorange data and the GPS correction data. The system minimizes the introduction of non-common errors by the use of double-differencing calculations using multiple combinations of satellite (108) and GPS ground station receiver (122).